Step 13: Spring 2010 Shading

Step 14: Winter 2012

Here is the greenhouse in a mild winter. I overwinter many potted perennials inside. To insulate the roof, I stretch a sheet of poly across the top t...

This is a brief guide on how I took some old windows from houses they where tearing down in my neighborhood and turned them into a small greenhouse in my back yard. I collected the windows over the course of a year and a half and the build took about 3 months, spending one day a week on it. I spent about $300 for the lumber for the frame and screws, caulk, latches, etc. That's almost 10% of what a greenhouse kit would cost. The size I built was 7 ft high x 10 ft deep x 6 ft wide. But the size of your greenhouse will depend on your windows and the time you want to put into project.

Step 1: Collect Windows and Plan Two Pair of Equal Sides.

Look for old windows and save every one you get. After you have many, lay them out and play a game trying to make two pairs of "walls" both the same height. Two to three inches won't matter as you can cover the difference with wood. Smaller holes will need to have glass cut for them or filled with something else. Keep in mind that one end will need a door and the other a hole for a fan.

Step 2: Create a Frame

Using the windows you chose as a guide, construct a frame for each wall. Use good lumber for this, as it is the structure that holds all the weight. I used all 2 x 4s for the studs and 4 x 4s for the corner posts. Choose a length that allows at least 14" of the stud to be placed in the ground for support.

Step 3: Brace Walls

Start placing the walls up, bracing well so they don't fall over. Be sure to check that they are level.

Step 4: Make the Foundation Secure

To avoid certain problems with pesky city building permits, I built the structure shed height and did not pour a concrete foundation. Instead I buried cinder blocks to stabilize the 4 x 4 corner posts. They keep it from moving an inch.

Cheft: could you be more explanatory about the foundation. I see in the pic, you have two boards attached to the 4x4. Did you leave them Both in? How did you attach the windows? Hinges? Screws? I have been collecting windows and want to do this, this summer. I am going to attach it on one side to a garage...any suggestions?

Another good source for old windows is Freecycle.org - you join one of the online groups that's in your own community - I moderate the one for Storrs CT. It's free. On these sites, you ask for/offer items. Always free. I see old windows offered on my site every month or so. And if you post a "Wanted" - you might just inspire someone to part with old windows sitting in their garage, barn, etc.

my husband and i have been collecting glass doors and old windows in hopes to build something very similar to this!! awesome inspiration!! absolutely love it! can't wait for spring so we can start on ours! woohoo! (wow - sorry about all the exclamation points, but this kind of stuff gets me excited. LOL) :o)

Great idea my wife mentioned this earlier tonight and look what pops up while browsing. Well I started collecting window tonight and hop to be able to get some better weather to work on this in my project garage and have it ready to go by spring. Living and gardening in MN make for some tough to do winter projects but I always mange to pull it off. Thanks for a good set set of plans and how to's they may come in handy.

i seen these here but i think i would like all the windows to be the same size and use a pole to open and close the top vent and have a closable window where the fan goes so when we have a bad winter i can close it.

When our local community gardening group was offered a bunch of windows by a guy who was remodelling an old house, we were told by our local county extension office that building a greenhouse from discarded windows was a bad idea because of the possibility of injury due to broken windows. Greenhouses should be paned with shatterproof substances because regular household window glass could break badly and seriously injure someone inside the greenhouse. Just a caveat.

that is why many use clear corrugated plastic sheeting for the roof, and windows for the walls. This also helps create moddled lighting as most plants prefer that to full sun and it will greatly decrease the odds of them burning, especially in a higher ambient humidity. :)

I have three greenhouse, and used regular windows for the construction. They have been in use now for more than 11 years, and with only five broken window panes. One from Hurricane Opal, the other four normal accidents that would have broken just about any window.

A warning about single pane ordinary glass hazards is warranted, BUT...

There should be no regulation preventing the use of used windows with single pane, single or double strength glass.

I to am in the process of trying to collect enough old windows to build a greenhouse of a reasonably usable size.

In the meantime, I got really lucky when a couple of neighbors replaced their large "patio" sliding glass doors. They each consisted of TWO glass panels [one fixed and the other sliding], giving me FOUR large double glazed [insulating] panels.

And the REALLY good thing about them is that they are both made with TEMPERED glass which is genrally much stronger, AND IF broken, shatters into hundreds of small "pebble-like," pea gravel sized pieces which are not as dangerous as the shards from broken ordinary glass.

Not yet having enough windows collected to build a greenhouse, I used the 4 double insulated panels to make four COLD FRAMES, which work great. Because of being double pane insulated panels, they each are very heavy, but with proper [ergonomically speaking] handles and automatic [gravity-pendelum action] prop rods, they are managable.

I made the cold frame bases of treated 2x4 framing, with the cavities filled with discarded Styrofoam sheeting [picked up wherever found discarded], covered with 1/2 inch treated plywood on the outside, and 1/2 inch untreated, but exterior grade, plywood on the inside. I then lined the interior walls with a construction water barrier film to give some limited protection to the plywood. To facilitate replacement of the interior plywood wall panels if it should ever be needed, I assembled the entire structure with Galvanized drywall screws.

Before varnishing, I carefully caulked all exterior crevices that might allow entry of weather [wind or water]. Finally, ALL outside wood exposed to weather was sealed with a properly applied [per label directions] triple coat of Polyurethane Varnish.

Unfortunately, I have no photos, AND have sold both cold frames a few years back. A "out-of-towner" guy made me an offer I couldn't refuse [$500 each], and so I've got to start over in the process of collecting tempered glass double insulated panels.

, you gave me associations to some thriller movie now. Can't remember what it was called, but a lady got "murdered by greenhouse"... I just love the greenhouse here, it is just sooo beautiful! Make me want a mini version for my balcony! Mine wouldn't be a walk-in model though, but rather a "closet" version... :)

this is exactly what i have been saving those windows for in my garage. I will be clearing some area near my compost pile.... what a great idea and thanks for the step by step!. I live outside of Chicago...

You have given me such inspiration. Our local court house was having their windows replaced. We scored 10 windows 35"'by38" and 10 windows 33"by35" and several more assorted sizes. All are double paned and we got the gasket around them. Couldn't get the channels. If we use 2" by 4"s and put a 1/2 inch channel in each to secure windows, would this give me enough structure safety? Don't know construction but really am inspired by you.

This is great. I have a lot of extra windows I got half price of very low prices, at the local Habitat for Humanity Restore....that would be a good source of reasonable windows.A neighbor made a green house of windows, he set it on concrete from an old barn that was on the property years before.

Very nice, also a good idea with the rocks. I used to have a similar setup in my garden, but it didn't last very long, because the wooden foundation was standing in mud and water during autumn and spring all the time, which resulted in it rotting away very fast. (I think we had to fix it after only 3 years)

If you decided to use railroad ties be careful how you use them. If they are separated from the greenhouse entirely (with non-porous floor) they probably won't be a problem. But they coat them with chemicals to prevent them from rotting and also they regularly spray pesticides on the tracks to kill the weeds. You probably don't want those chemicals near you or your plants, especially if you are growing anything edible. Just something to watch out for.

Great Instructable. If you need windows, check with your local window/glass supplier/installers. Most will let you have the old windows they remove from home renovations, especially if you give them a wish list. Otherwise they have to pay to take them to the landfill.

Our local landfill has a recycle section. When you go to toss something, if it is recyclable, you get to leave it there for free (you get to do that with some other things too, but you have to sort them into different bins yourself). It's a big building, and people come there to leave all kinds of things for the home they don't need anymore and others come to find free furniture etc. etc. Think I'll have to go to see if there are any windows there. If something hasn't been claimed by somebody else within a week, the landfill people remove it and discard it. It's just like a second hand store for things for the home, only it is free for all. :) All landfills should do that, what a wonderful way to reduce the amount of garbage and great for those with little money... :)